IN VITRO COMPARISON OF TENSILE RETENTIVITY OF CAST METAL AND READY MADE POSTS CEMENTED WITH SOME DIFFERENT LUTING AGENTS

Abstract

A comparative study on the retentivity of different designs of posts cemented by· three luting agents was done on seventy five freshly extracted human maxillary central incisors. The teeth were classified according to the types of post design tested into five equal groups as follows: I. Tapered smooth sided cast metal post. 2. Smooth parallel sided cast metal post. 3. Ready made stainless steel threaded post. 4. Ready made stainless steel split shaft post and, 5. Ready made stainless steel serrated parallel sided post. The root canals of the teeth were mechanically prepared to receive the required type of post using the recommended driller. In order to standerdize the method of testing, all the canals were prepared to· be with equal length of 8.6 mm and equal diameter of· 1.65 mm. Each prepared sample was fixed in an acrylic resin block using a specially constructed root block fonner. The posts were cemented in the prepared root canals by zinc phosphate, glass ionomer and resin luting agents under constant pressure using special load applicator. The cementation procedures was done exactly following the manifacturers directions. The tensile force required to dislodge the post from the root canals was applied and determined by a universal testing machine.